HTML canvas ImageData data Property
Example
Create a 100*100 pixels ImageData object where every pixel is set to the color red:
Canvas
JavaScript:
var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
var imgData=ctx.createImageData(100,100);
for (var i=0;i<imgData.data.length;i+=4)
{
imgData.data[i+0]=255;
imgData.data[i+1]=0;
imgData.data[i+2]=0;
imgData.data[i+3]=255;
}
ctx.putImageData(imgData,10,10);
Try it Yourself »
Browser Support
The numbers in the table specify the first browser version that fully supports the property.
| Property | |||||
|---|---|---|---|---|---|
| data | 4.0 | 9.0 | 3.6 | 4.0 | 10.1 |
Definition and Usage
The data property returns an object that contains image data of the specified ImageData object.
For every pixel in an ImageData object there are four pieces of information, the RGBA values:
R - The color red (from 0-255)
G - The color green (from 0-255)
B - The color blue (from 0-255)
A - The alpha channel (from 0-255; 0 is transparent and 255 is fully visible)
The color/alpha information is held in an array, and is stored in the data property of the ImageData object.
Examples:
The syntax for making the first pixel in the ImageData object red:
imgData=ctx.createImageData(100,100);
imgData.data[0]=255;
imgData.data[1]=0;
imgData.data[2]=0;
imgData.data[3]=255;
The syntax for making the second pixel in the ImageData object green:
imgData=ctx.createImageData(100,100);
imgData.data[4]=0;
imgData.data[5]=255;
imgData.data[6]=0;
imgData.data[7]=255;
Tip: Look at createImageData(), getImageData(), and putImageData() to learn more about the ImageData object.
JavaScript Syntax
| JavaScript syntax: | imageData.data; |
|---|
Canvas Object
